Catecholaminergic systems have been implicated in both the pathogenesis of stroke and the recovery of function after ischemic injury. This proposal is designed to further elucidate the structure, regulation and function of the a1-adrenergic receptor ( a1-AR ) for catecholamines. a1-AR mediated events may play a role in the control of the cerebral circulation in man. In addition, the a1-AR may directly influence cellular metabolism through the putative second messengers inositol trisphosphate and diacylglycerol. This may be important for the understanding of neuronal growth, plasticity and altered neurotransmission. The work has three specific aims: 1) to develop technologies for the purification of the necessary quantities of receptor protein, 2) to raise antibodies directed against the a1-AR and, 3) to develop a system for the reconstitution of the a1-AR into phospholipid vesicles. Purification of the receptor protein will be accomplished through sequential affinity chromatography, wheat germ agglutinin chromatography, and high performance steric-exclusion liquid chromatography. Purified receptor will then be employed to immunize rabbits for the production of antibodies. A reconstitution system will provide a means of assaying the activating function of the receptor and a way of studying the mechanisms by which the receptor-effector system is regulated. Combined with previous work, the availability of these biochemical tools will permit further study of the a1-adrenergic receptor at the molecular level.